For the past several years I have been chasing information on the Bataan Military Plant (headstamp: BMP) to see if they made 9x19. It now seems that their production was limited to 5.56mm with the known dates being 91 and 93.
There are also 5.56mm headstamped RPA (Republic of the Philippines Army, or perhaps Republic of the Philippines Arsenal) from the late 1980s. They also made at least one lot of 9x19mm in 1997. The box label for the 9x19mm with the RPA headstamp states:
Department of National Defense
Camp General Antonio Luna
The obvious question is whether these are actually only a single plant, or are there (were there) two military ammunition plants in Bataan?
Perhaps they used one headstamp (RPA) for ammunition for the Army and a different headstamp (BMP) for ammunition for the police or whoever.
I have never seen an address associated with the Bataan Military Plant.